Dodging and burning is a technique which helps to exaggerate tonal differences already present in the image. The trick is to examine your image, identify the lighter and darker part of your image then dodge (lighten) and burn (darken) intelligently to bring these differences out.
Whilst there are Dodge and Burn tools in the Toolbox of Photoshop, another more subtle way to dodge and burn is to use the Brush Tool in conjuction with the default foreground/background colours in the Layers palette as follows:
1. Hold Alt and click the ‘New Layer’ button on the Layers palette.
2. Change the blending mode to ‘Overlay’ and click the box ‘Fill with Overlay-neutral color(50% grey).
3. Duplicate this layer, and name one of them ‘Burn’ and the other ‘Dodge’.
Using a low opacity brush (5-15%) paint with black onto the ‘Burn’ layer to darken things, and with white on the ‘Dodge layer’ to lighten things - effectively increasing contrast. As we’re painting on layers, this effect is non-destructive to the original image. If you make a mistake, just hit the Undo button or you can paint out your error with opposite brush.
Remember to keep down your mouse button whilst painting as every time you click on it the more you paint over the image and darker or lighter it becomes. Subtle adjustments are the key so the processing of the image doesn’t look overdone.
One of my favourite post processing techniques to enhance landscape images is known as Painting with Light (PWL). This is a form of the dodging and burning technique, which helps to exaggerate tonal differences already present in the image.
In the Layers Palette create two new layers above background: